When a VCSEL (vertical-cavity surface-emitting laser) lases in multiple transverse modes, and the output of the VCSEL propagates in an optical fiber, different modes are excited in the optical fiber that travel at different velocities. This phenomenon is known as modal dispersion, and the data signal pulses spread into wider pulses as they propagate along the fiber. The higher the data rate, the closer the data pulses are spaced. Thus, the link distance is limited by the distance over which the pulse widths do not increase enough to interfere with neighboring pulses. In data centers, optical signals may be routed over distances from about 50 meters up to a few kilometers. Thus, the impact of modal dispersion may prevent high data rate transmission systems from operating in a data center.